The transmission of data signals over a communication network is subject to various problems in a transmission medium or channel. Problems such as noise, channel fading and multipath may cause errors in decoding the transmitted signal. To counter these problems, additional or redundant information is transmitted with the signal. A corresponding receiver would use this redundant information to perform error correction on the received signal. Otherwise, the receiver may either erroneously decode the received signal or require retransmission of the data signal.
In a digital data signal, the additional information is typically in the form of additional or redundant bits in a digital bit sequence. For example, to provide error correction in an MPEG-2 (MPEG: Moving Pictures Expert Group) packet, twenty additional bytes are added to the 179 bytes of data. Moreover, to combat severe channel interference, the amount of additional bits may approach the amount of data transmitted. A convolutional encoder having a 0.5 code rate would, for example, generate eight output bits for every four input bits of the digital bit sequence.
The use of additional error correcting bits is provided at the expense of having a lower data transmission rate. As such, if the transmission medium or information channel is of high quality, these additional error correcting bits creates an unnecessary overhead for the receiver. Therefore, a need exists in the art to reduce the number of redundant bits transmitted over existing error correction techniques.